This invention relates to a print mask switching device in a photographic printing unit. More particularly, it relates to a print mask switching device having means for opening and closing a print paper guide which is provided for each print mask to close the opening thereof.
In the operation of a photographic printing unit, it is necessary to change the print mask not only where the size of the print paper is changed, but also where, although the size of the print paper is unchanged the manner of exposure thereto is changed. For example, in the case where printing a picture with no frame is switched over to printing a picture with a frame, or vice versa, the mask must be changed even though paper size remains constant.
In such a case, with a conventional photographic printing unit, the print paper loading section is opened to replace the print mask. For this replacement operation, it is necessary to utilize a room dark environment where the photographic printing unit is installed. Alternatively, a dark bag may be provided at the print paper loading section and is used to replace the mask blindly by feel. Thus, both of these methods are rather troublesome and inefficient.
When print paper is loaded in the print mask which has been set in place, it is necessary to close the opening (or window) of the print mask with a print paper guide so that the print paper may not come out through the opening and may be smoothly fed. In addition, after the print paper has been loaded, the closing member should be removed quickly. Heretofore, this operation is also carried out blindly by feel similar to the replacement of the print mask, and is in fact more troublesome than the print mask replacement.